Atlético Madrid's on-loan goalkeeper Thibaut Courtois admits that he still does not know where he will play next season, insisting that he must wait for his parent club, Chelsea, to make a decision about his future, but he warned that he will not accept a substitute's role.

Courtois, speaking after Atlético had become Spanish champions for the first time in 18 years, said: "It's a great feeling to be champion of Spain. I am not sure yet what happens next season. We have the Champions League final [on Saturday] and then the World Cup, so now is not the time to think of the future. I have two years contract [left] with Chelsea, so we will see.

"If I move somewhere, I will play. With my age, what I want, the most important thing for me, is to play. We will see what happens. But Petr [Cech] is one of the best goalkeepers in the world, he won the golden glove in the Premier League, and I have a lot of respect for him, so we will see what Chelsea decide and what they plan to do. You guys will see the decision [then]."

Courtois turned 22 a week ago. Last summer, Chelsea preferred the young goalkeeper to go on loan to another English club to prepare him for Premier League football, but the Belgian insisted that it was better to stay in Spain. He has now won four titles and two consecutive Zamora awards as La Liga's best goalkeeper. His manager describes him as the best in the world. "He is my coach, so he would always have to say that about his goalkeeper," Courtois smiled. "He gave me more confidence when he arrived here, and with him I have grown a lot as a goalkeeper.

"When I joined [Atlético] three years ago it was not sure I would stay three years. I stayed one year and said I would see. We won the Europa League, the European Super Cup and then the next year it was the Copa del Rey and now it's the [league] title. It was unthinkable to achieve all of those things."

Courtois described what Atlético are going through as "more than a fairy tale" and cited Diego Simeone as the key to the change in the club's mentality. "When he arrived, he made it very hard to score against us," the Belgian said. "He made this system, he knew how to make the team play. It starts with good organisation, good defence with no risk, and then a good counter-attack. We are a good team with a good coach and we are one team together and we have seen that one team can do more than 11 top players. You can see what we have achieved."

"[Simeone] will only say two or three words but he says it in the right way. Today we saw a video that started in pre-season and showed all the important goals and important saves [from the season], all of the work that we had done to achieve what we did. He did not have to say a lot more. In July, we had to work very hard to be very ready for all of these games. It is a beautiful thing.

"At half-time [in Saturday's title-clinching 1-1 draw at Barcelona], he told us that we were better than them. It was just details, and he talked some tactics, about how to defend more, to press Fábregas and Iniesta. We started the second half very well. When I was 16 years old, I hadn't played my first [professional] game. I never would have thought that five or six years later I would be here."

The Atlético CEO, Miguel-Ángel Gil Marín, meanwhile, has admitted that a deal for Courtois to continue in Spain for another season had been put on hold after the Champions League draw brought the club together with Chelsea.

José Mourinho did not want Courtois to play in the semi-final and a clause in his contract imposed a penalty, understood to be around €6m. Uefa insisted that Chelsea could not prevent him from playing and in the end Courtois was included for both legs, making a stunning save at Stamford Bridge. "It was all agreed but the draw bringing us together in the Champions League and the payment of the clause put the operation on hold," Gil Marín said. "What happens with him will be decided after the Champions League final."